viced: null-terminate server list for ubik

viced: null-terminate server list for ubik

when we set up the vlserver connection, we could potentially use
uninitialized memory as ubik connections. don't.

Change-Id: Idefa71874c7402c927fbf148f994f9422183208a
Reviewed-on: http://gerrit.openafs.org/7610
Reviewed-by: Simon Wilkinson <simonxwilkinson@gmail.com>
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: Derrick Brashear <shadow@dementix.org>
Tested-by: BuildBot <buildbot@rampaginggeek.com>